Air guiding means for drying apparatus



Feb. 20, 1962 H. FLEISSNER AIR GUIDING MEANS FOR DRYING APPARATUS Filed June 16, 1959 ilnite States l atent Q 3,il21,6ll8 AER GUEING lVl'EANS FGR DRYING APPARATUS Hans Fleissner, Wolfgraienstrasse 6, Egelsbach, Germany Filed dune 16, 1959, Ser. No. 320,808 Claims priority, application Germany June 18, 1958 ll) Claims. (Cl. 34l15) The present invention relates to an air guiding means for drying apparatus, and more particularly to an arrangement for deflecting air directed in a stream against perforated drying drums.

Drying apparatus using perforated drums must be supplied with a sufiiciently large quantity of circulating air to effect the drying process, since otherwise the system operates inefiiciently.

While the drying process also depends on the temperature of the circulated air, the temperature is limited by the type of material which is dried, and faster drying can only be obtained by an increase of the amount of circulated air.

This causes difliculties when band-shaped material, and particularly very thin ribbons or filaments are conveyed by the perforated drying drums, since such material covers only a small part of the perforated drum surface. The bands must have a minimum distance from each other in axial direction of the drum, to avoid entanglement with adjacent hands when displaced by a high velocity stream of drying air. Band-shaped material does not offer any particular resistance to the passage of air from the outside into the interior of a drying drum, so that the circulated air impinges with full force on the periphery of the drying drums.

The impinging air stream is divided by the drum, and flows on opposite sides of the drum. Due to the rotation of the drum, one side of the drum surface moves in direction of one part of the air stream, while the other side of the drum moves substantially in opposite direction to the direction of movement of the air. On this side the stream of air blows against the material on the drum surface in a direction opposite to the direction in which the material is conveyed, so that the band-shaped material is displaced, which particularly takes place at the leading end portions of the band-shaped material.

A displacement of the band-shaped material particularly takes place where two adjacent perforated drums form a bight in which the material passes from one of the drums to the adjacent drum, and consequently changes its curvature in the opposite direction.

It is the object of the present invention to overcome this disadvantage of known drying apparatus, and to provide means for guiding the air toward the drying drums and the material thereon in such a manner that the streams of air impinging the material have at least a component in the direction of movement of the material conveyed by the rotating drying drums.

Another object of the present invention is to prevent a displacement of material conveyed by drying drums by a stream of air moving in a direction opposite to the direction in which the material is conveyed.

Another object of the present invention is the provision of guiding means for deflecting part of the stream of air impingin a drying drum so that the deflected stream of air assumes a direction of flow defining acute angles with the radius and the tangent of the drying drum in the region of the guide means.

With these objects in view, the present invention mainly consists in a drying apparatus which comprises, in combination, at least one rotary perforated tubular member or drying drum on which a material is supported and conveyed; means for producing a stream of a gaseous medium in a direction transverse to the axis of rotation of the tubular member so that a peripheral portion of the tubular member is impinged by the stream whereby parts of the stream flow along the sides of the peripheral portion of the tubular member; and guiding means for the gaseous medium and located on the side of the peripheral portion of the tubular member where the peripheral portion and the material thereon move substantially opposite to the direction of the flow of the stream of gaseous medium. The guiding means have an inlet portion farther spaced from the peripheral surface of the tubular member or drum and extending substantially in the direction of the stream of gaseous matter. The outlet portion of the guiding means is closer spaced from the tubular member and is shaped for deflecting the gaseous medium to move toward and through the perforated tubular member in a direction having at least a component in the direction of movement of the peripheral portion and of the material conveyed thereon. In this manner, the deflected stream of air tends to hold the material on the surface of the tubular member, while otherwise the respective part of the air stream, moving in a direction substantially opposite to the directionof the movement of the material on the tubular member,

would tend to displace the material so that it may become entangled.

In the preferred embodiment of the present invention, the guiding means include a plurality of guideplates which are curved to gradually deflect the air stream, and have outlet portions which define acute angles with the the tangent and with the radius of the adjacent portion of the respective tubular drying drum.

In order to prevent that the stream of air passes transversely through the perforate drying drum, 1a stationary shield is provided in each drying drum for covering the peripheral portion of the drying drum where no material is located which is impinged by the stream of air. The thus covered portion of each drying drum is located adjacent an impinged portion of an adjacent drying drum, which is provided with the guiding means of the present invention. Preferably, one guide plate of the guiding means has a curved portion located within the space between the shield and the periphery of the drying drum, while another plate portion is located in the bight between the adjacent drying drums for guiding the air against the material in such a direction as to have a component in the direction of movement of the conveyed material.

The drying drums are enveloped in a housing, and two opposite streams are directed from opposite sides of the housing towards the drying drums. According to a preferred embodiment of the present invention, a curved perforate sheet is located outwardly and radially spaced from the impinged peripheral portion of a drying drum, and adjacent the respective guide means. Air passing through the perforate sheet is slightly deflected in direction of the movement of the material.

The guide plates forming the guiding means may have inlet portions extending to the inlets of the housing means, or be spaced from the housing means. Preferably, the inlet portions of the guiding means are more closely spaced, and the outlet portions are farther spaced apart to form flaring channels for the deflected air stream.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary schematic cross sectional view of a drying apparatus according to one embodiment of the present invention; and

FIG. 2 is a fragmentary schematic cross sectional view of a modified embodiment of the present invention.

Referring now to the drawings, a material 20 is conveyed in direction of the arrows 21 on portions of the tubular members 1, 2, 3 and 4 and along a tortuous path. The tubular members or drying drums 1, 2, 3, 4 have parallel axes of rotation, with the axes of alternate drums located in parallel planes. In the arrangement of FIG. 2, two drying drums 1 and 2 are provided whose axes are located in a common plane.

Stream lines 6 indicate in both figures the flow direc tion of the streams of gaseous medium which are supplied into the housing 34} by conventional blower means, not illustrated in the drawing. As is apparent from FIGS. 1 and 2, streams of air flow in opposite directions toward the drying drums so that the peripheral portions of the drums 1 and 3 located :in the upper part of FIG. 1 are impin ed by one stream of air, and the peripheral portions of the drums 2 and 4 located in the lower portion of FIG. 1 are impinged by the opposite stream of air. In order to prevent the air from flowing directly through the perforate drums, shielding means Ill, 12, 13 and 14 are provided within the drums along the perforate portions of the same which are not covered by the material 20.

The streams of air 6 fiow along the sides of the impinged portions of the drums, and it will be noted that the part of the stream of air located on the right side of drum 3, as viewed in FIG. 1, will have a component in the direction of movement of the material 20 and tend to hold the material on the drum. The air passes through the material, through the perforate drum surface, and into the interior of the drums from where it is removed by conventional suction means which are not an object of the present invention. On the left side of drum 3, as viewed in FIG. 1, the stream of air has a direction which is opposite to the direction of movement of the material 20 conveyed on drum 3, as also seen on the left side of drum 2. It is evident that the leading end of bands conveyed over the drums, may be blown back and become entangled by such opposing streams. To prevent such disturbances, guiding means are provided in accordance with the present invention for deflecting air moving in a direction opposite to the movement of the material until such deflected air has at least a component in the direction of movement of the conveyed material. Tubular member 3 is shown to be provided with guiding means 7 which comprise a plurality of guide plates 71. The guide plates 71 have inlet portions extending to the housing means 39 and receiving the stream of air which passes through inlets in the housing means, not shown. The inlet portions extend in direction of the flow of the stream of air, while the outlet portions 72 of the guide plates curve back and terminate in portions extending at acute angles to the radius of drum 3 and to the tangent on the respective peripheral portion of drum 3. The arrows indicating the stream lines of the air stream clearly indicate that the deflected air has a radial component passing through the material 20 and through the perforate tubular member 3 into the interior of tubular member 3, while tending to press the material firmly against the surface of tubular member 3. Another component, acting in tangential direction, acts in direction of movement of the conveyed material 20.

FIG. 1 further illustrates how the space between tubular member 2 and the shield 12 therein is utilized for the guiding means according to the present invention. A curved plate 8 is located in the space between the tubular member 2 and the respective shield 8, and another plate member Si is located in the bight between the tubular members '2 and 3. The outermost guide plate 73 constitutes an inlet portion, the curved plate 8 constitutes an intermediate portion, and the curved plate "r 81 constitutes the outlet portion of the respective guide means which is of a general configuration correspond ing to the shape of the other guide plates 71. The arrangement prevents a stream of air to enter the space between the drums 2 and 3 through the space between the shield 8 and the perforate periphery of drum 2. Such air stream would disturb and entangle the leading portions of a band-shaped material while the same passes from the surface of drum 2 to the surface of drum 3.

The guide plates of the guiding means 7 have rather long inlet portions, closely spaced from each other which renders access to drum 3 difficult. A modified construction of the guiding means of the present invention is illustrated on the left side of tubular member 4. Guide plates 10 are provided having short inlet portions extending in direction of the air stream 6, and outlet portions which curve back and terminate in portions defining acute angles with the tangential and radial directions of drum 4 as described with reference to guiding means 7. The outermost guiding plate includes a portion 8 located in the space between the shield 13 and the peripheral surface of drum 3, and a part 81 located in the bight between drums 3 and 4. A smaller number of guiding plates 10 is provided, so that a portion of drum 4, and of the material thereon, would be impinged by an air stream 6 having a component directed opposite to the direction of movement of the material 20.

In accordance with the present invention, a curved perforate sheet 9 is provided outwardly of and radially spaced from the periphery of drum 4, and is impinged by the stream of air 6.

The greater part of the impinging air flows along sheet 9, and therefore cannot entangle the material 20 moving in a direct'on opposite thereto. A part of the air passes through the perforations in sheet 9 and is deflected to urge the material 20 against the surface of drum 4. It will be appreciated that corresponding guiding means for deflecting the air are advantageously provided on the left side of drum 2 as viewed in FIG. 1.

In the embodiment of FIG. 2, the material 20 is guided along two tubular members 1 and 2, and is held in position by rotary rollers 22. Stationary shields 11 and 12' are provided in drums 1 and 2', and have projecting plates and 120. Long guide plates 40 and 41 direct the streams of air 6a and 6b, respectively, toward drums 2' and 1', respectively. The guide plate means 40 includes a portion 48 located in the space between shield 11 and the perforated tubular member 1, and the guide plate means 41 has a corresponding portion 42 located in the space between shield 12' and the perforated wall of drum 2. A plate 38 is located in the bight between drums 1 and 2' and constitutes an extension of plate portion 48 for deflecting the stream of air 6a in direction of the moving material 20, as described with reference to FIG. 1. The drum 1' is provided with guiding means 7 including a plurality of guide plates 25 which are curved as described with reference to the guide plates 71 of the guide means 7 shown in FIG. 1. A modified construction is shown for drum 2 according to which a plurality of short guiding plates 10 is provided in the region of the bight between the drums 1' and 2', while a perforated sheet 9 is provided to prevent direct impingement of the material 20 by streams of air 6:: which have components extending opposite to the direction of movement of the material. As explained with reference to FIG. 1, sheet 9 deflects the stream of air sufiiciently to prevent entanglement of leading portions of a band conveyed by drums 1' and 2'.

It will be understood that the embodiment including the guiding means 9 and 10 could be provided for all drums, and that the embodiment including only guiding means 7 could be provided for all drums. Different embodiments are shown in the drawing for each drum to facilitate the explanation of the several embodiments of the present invention. The guiding means 7, 10 and 9 extend in axial direction of the respective drums along the entire length of the drums. The interior of each drum communicates in a conventional manner with the inlet means of a blower whose outlet means are connected to inlets in housing 30 to provide the oppositely directed air streams explaned with reference to FIGS. 1 and 2. The shields 11, 12, 13, 14, and 11', 2' close the perforated walls of the drums on the sides where no material is supported, so that no air can be sucked through the drum portions which are covered by the shields.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of drying apparatus differing from the types descrbed above.

While the invention has been illustrated and described as embodied in an air guiding means for a drying apparatus, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any Way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applcations without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaining and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. Drying apparatus comprising, in combination, at least one rotary perforated tubular member adapted to support and convey a material thereon; means for producing a stream of a gaseous medium in a direction transverse to the axis of rotation of said tubular member so that a peripheral portion of said tubular member is impinged by the stream whereby parts of the stream fiow along the sides of said peripheral portion of said tubular member; and guiding means for the gaseous medium and located on the side of said peripheral portion of said tubular member where said peripheral portion of said tubular member and the material thereon move substantially opposite to the direction of the flow of the stream, said guiding means having an inlet portion farther spaced from said tubular member and adapted to extend substantially in the direction of the stream and an outlet portion closer spaced from said tubular member and being shaped for deflecting the gaseous medium to move toward and through said perforated tubular member in a direction having at least a component in the direction of movement of said side of said peripheral portion and of the material conveyed thereon for holding said material on said tubular member.

2. Drying apparatus comprising, in combination, at least one rotary perforated tubular member adapted to support and convey a material thereon; means for producing a stream of a gaseous medium in a direction transverse to the axis of rotation of said tubular member so that a peripheral portion of said tubular member is impinged by the stream whereby parts of the stream flow along the sides of said peripheral portion of said tubular member; and guiding means for the gaseous medium and located on the side of said peripheral portion of said tubular member where said peripheral portion of said tubular member and the material thereon move substantially opposite to the direction of the flow of the stream, said guiding means having an inlet portion farther spaced from said tubular member and adapted to extend substantially in the direction of the stream and an outlet portion closer spaced from said tubular member and curving back for deflecting the gaseous medium to move toward and through said perforated tubular member in a direction having at least a component in the direction of movement of said side of said peripheral portion and of the material conveyed thereon for holding said material on said tubular member, said outlet portion defining acute angles with the tangent and with the radius of said tubular member on said side of said peripheral portion in the region located opposite said outlet portion.

3. Drying apparatus comprising, in combination, at least one rotary perforated tubular member adapted to support and convey a material thereon; means for producing a stream of a gaseous medium in a direction transverse to the axis of rotation of said tubular member so that a peripheral portion of said tubular member is impinged by the stream whereby parts of the stream flow along the sides of said peripheral portion of said tubular member; guiding means for the gaseous medium and located on the side of said peripheral portion of said tubular member where said peripheral portion of said tubular member and the material thereon move substantially opposite to the direction of the flow of the stream, said guiding means having an inlet portion farther spaced from said tubular member and adapted to extend substantially in the direction of the stream and an outlet portion closer spaced from said tubular member and curving back for deflecting tl e gaseous medium to move toward and through said perforated tubular member in a direction having at least a component in the direction of movement of said side of said peripheral portion and of the material conveyed thereon for holding said material on said tubular member; and a curved perforate sheet extending over said impinged peripheral portion between said sides, outwardly of and radially spaced from said impinged peripheral portion of said tubular member and adjacent said guide means for partly deflecting the stream impinging thereon and passing therethrough.

4. Drying apparatus comprising, in combination, at least one rotary perforated tubular member adapted to support and convey a material thereon; means for producing a stream of a gaseous medium in a direction trans-' verse to the axis of rotation of said tubular member so that a peripheral portion of said tubular member is impinged by the stream whereby parts of the stream flow along the sides of said peripheral portion of said tubular member; and guiding means for the gaseous medium and located on the side of said peripheral portion of said tubular member where said peripheral portion of said tubular member and the material thereon move substantially opposite to the direction of the flow of the stream, said guiding means including a plurality of guide plates, each guide plate having an inlet portion farther spaced from said tubular member and adapted to extend sub-v stantially in the direction of the stream and an outlet portion closer spaced from said tubular member and curving back for deflecting the gaseous medium to move toward and through said perforated tubular member in a direction having at least a component in the direction of movement of said side of said peripheral portion and of the material conveyed thereon for holding said material on said tubular member, said outlet portions defining acute angles with the tangent and with the radius of said tubular member on said side of said peripheral portion in the region opposite the respective outlet portion, said guide plates defining with each other channels for the stream, said inlet portions being closer spaced from each other and said outlet portions being farther spaced from each other so that said channels widen toward said tubular member.

5. A drying apparatus as set forth in claim 4 wherein said guide plates are adjustable.

6. A drying apparatus comprising, in combination, a plurality of rotary perforated tubular members having parallel axes of rotation and being adapted to support and convey a material along a tortuous path along peripheral portions thereof; means for producing streams of a gaseous medium in directions transverse to the axes of 'i' rotation of said tubular members so that said peripheral portions of said tubular members are impinged by the stream whereby parts of each stream flow along the sides of said peripheral portions of said tubular members, the streams impinging adjacent tubular members flowing in opposite directions; stationary shielding means located in each tubular member spaced from and opposite the remaining peripheral portions of said tubular members where no material is located; and guiding means for the gaseous medium located on the sides of said peripheral portions of said tubular members Where the surfaces of said tubular members and the material thereon move substantially opposite to the direction of flow of the stream, each guiding means having an inlet portion farther spaced from the respective tubular member and adapted to extend substantially in the direction of the respective stream, and having an outlet portion closer spaced from the respective tubular member curving back and defining angles with the tangent and with the radius of the respective tubular member on said side of said peripheral portion in the region located opposite said outlet portion for deflecting the gaseous medium to move toward and through the respective perforated tubular member in a direction having at least a component in the direction of movement of said side of said peripheral portion and of the material conveyed thereon whereby said material is held on said tubular members, at least one of said guiding means having a portion located in the space between said shielding means and said remaining peripheral portion of the tubular member which is located adjacent the tubular member with which said one guiding means is associated.

7. A drying apparatus comprising, in combination, a plurality of rotary perforated tubular members having parallel axes of rotation and being adapted to support and convey a material along a path along peripheral portions thereof; means for producing streams of a gaseous medium in directions transverse to the axes of rotation of said tubular members so that said peripheral portions of said tubular members are impinged by the stream whereby parts of each stream flow along the sides of said peripheral portions of said tubular members; stationary shielding means located in each tubular member spaced from and opposite the remaining peripheral portions of said tubular members where no material is located; and guiding means for the gaseous medium located on the sides of said peripheral portions of said tubular members where the surfaces of said tubular members and the material thereon move substantially opposite to the direction of flow of the stream, each guiding means having an inlet portion farther spaced from the respective tubular member and adapted to extend substantially in the direction of the respective stream, and having an outlet portion closer spaced from the respective tubular member and curving back for defining angles with the tangent and with the radius of the respective tubular member on said side of said peripheral portion in the region located opposite said outlet portion for deflecting the gaseous medium to move toward and through the respective perforated tubular member in a direction having at least a component in the direction of movement of said side of said peripheral portion and of the material conveyed thereon whereby said material is held on said tubular members.

8. A drying apparatus comprising, in combination, a plurality of rotary perforated tubular members having parallel axes of rotation and being adapted to support and convey a material along a tortuous path along peripheral portions thereof; means for producing streams of a gaseous medium in directions transverse to the axes of rotation of said tubular members so that said peripheral portions of said tubular members are impinged by the stream whereby parts of each stream flow along the sides of said peripheral portions of said tubular members, the streams impinging adjacent tubular members flowing in opposite directions; stationary shielding means located in each tubular member spaced from and opposite the remaining peripheral portions of said tubular members where no material is located; and guiding means for the gaseous medium located on the sides of said peripheral portions of said tubular members Where the surfaces of said tubular members and the material thereon move substantially opposite to the direction of flow of the stream, each guiding means including a plurality of guide plates, each guide plate having an inlet portion farther spaced from the respective tubular member and adapted to extend substantially in the direction of the respective stream, and having an outlet portion closer spaced from the respective tubular member and defining acute angles with the tangent and with the radius of the respective tubular member on said side of said peripheral portion in the region located opposite said outlet portion for deflecting the gaseou medium to move toward and through the respective perforated tubular member in a direction having at least a component in the direction of movement of said side of said peripheral portion and of the material conveyed thereon whereby said material is held on said tubular members, said guide plates of each guiding means defining with each other channels Widening toward the respective tubular member, said inlet portions of said guide plates being closer spaced from each other than said outlet portions.

9; A drying apparatus as set forth in claim 8 and including a housing enveloping said tubular members and having inlets at opposite sides for said streams of gaseous medium.

10. A drying apparatus comprising, in combination, a plurality of rotary perforated tubular members having parallel axes of rotation and being adapted to support and convey a material along a tortuous path along peri heral portions thereof; means for producing streams of a gaseous medium in directions transverse to the axes of rotation of said tubular members so that said peripheral portions of said tubular members are impinged by the stream whereby parts of each stream flow along the sides of said peripheral portions of said tubular members, the streams impinging adjacent tubular members flowing in opposite directions; stationary shielding means located in each tubular member spaced from and opposite the remaining peripheral portions of said tubular members where no material is located; and guiding means for the gaseous medium located on the sides of said peripheral portions of said tubular members where the surfaces of said tubular members and the material thereon move substantially opposite to the direction of flow of the stream, each guiding means including a plurality of guide plate means, each guide plate means having an inlet portion farther spaced from the respective tubular member and adapted to extend substantially in the direction of the respective stream and an outlet portion closer spaced from the respective tubular member curving back and defining angles with the tangent and with the radius of the respective tubular member on said side of said peripheral portion in the region located opposite said outlet portion for deflecting the gaseous medium to move toward and through the respective perforated tubular member in a direction having at least a component in the direction of movement of said side of said peripheral portion and of the material conveyed thereon whereby said material is held on said tubular members, at least one of said guide plate means of at least one of said guiding means including a curved plate portion located in the space between said shielding means and said remaining peripheral portion of the tubular memher which is located adjacent the tubular member with which said one guiding means is associated, and an extension plate located between adjacent tubular members and constituting part of the outlet portion of said one guide plate means.

References Cited in the file of this patent FOREIGN PATENTS Great Britain Dec. 19, 1956 

